Calendar sync on iPhone: keep all events updated

The short version

If your iPhone calendar doesn't match your computer, you'll get double-booked. Here's the quick fix:

1. Add your accounts in Settings. On iOS 18 and later, go to Settings > Apps > Calendar > Calendar Accounts to add your Google or Outlook account. On iOS 17 and earlier it's Settings > Calendar > Accounts.
2. Turn on Push. New events then show up right away instead of on the next 15-minute check.
3. Check your default calendar. Make sure new events aren't saving to your phone only.
4. Use a sync tool for real blocking. If personal events need to block time on your work Outlook calendar, the built-in options can't do it. Caltsu syncs the Google and Microsoft accounts you use on your iPhone.

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You check your phone in the morning. Nothing until 11 AM. Good time for a coffee run.

Then you get to your desk, open your laptop, and your stomach drops.

Your work calendar has a client meeting at 9:30 AM.

This is a common iPhone calendar sync problem. Apple's Calendar app looks good, but it doesn't always work smoothly with Google or Microsoft out of the box.

If meetings keep failing to show up on your phone, this guide walks through the fixes.

How iPhone calendar sync works (or doesn't)

Your iPhone doesn't hold your calendars itself. The Calendar app shows events from your accounts, whether that's iCloud, Google or Outlook.

When you add an event on your phone, the phone sends it to that account's server, say Google's. The server then passes it to your laptop. If that connection is slow or broken, you get events that exist on one device and nowhere else.

Most sync problems come down to two things:

• The account is added, but its Calendars switch is off.
• The phone is saving battery and only checks for new events every hour.

Here's how to fix both.

How to sync your iPhone with Google Calendar

Google and Apple are rivals, but you can still pull your Google events into the Calendar app that came with your iPhone. You don't need the Google Calendar app.

1. Open Settings on your iPhone.
2. Go to Apps > Calendar > Calendar Accounts. On iOS 17 and earlier, tap Calendar > Accounts.
3. Tap Add Account.
4. Choose Google and sign in with your Gmail account.
5. After you sign in, you'll see a list of things to sync, such as Mail, Contacts and Calendars. Make sure Calendars is switched on. This is the step people miss.
6. Tap Save.

Give it a couple of minutes. Then open the Calendar app, tap Calendars at the bottom, and check that your Gmail address is ticked.

Shared Google calendars, like "Team Holidays", may not show up right away. Open google.com/calendar/syncselect in your phone's browser and tick the calendars you want. The page looks ancient, but it's the only place to choose which shared calendars reach your iPhone.

How to sync your iPhone with an Outlook calendar

Most companies run on Outlook, and a missed work meeting usually hurts more than a missed personal reminder.

1. Go to Settings > Apps > Calendar > Calendar Accounts, or Settings > Calendar > Accounts on iOS 17 and earlier.
2. Tap Add Account.
3. Choose the right option:
   • Outlook.com for personal accounts, including Hotmail and Live.
   • Microsoft Exchange for most work accounts.
4. Enter your email and password. Your IT department may require two-factor authentication, so keep your authenticator app handy.
5. Make sure Calendars is switched on.
6. Tap Save.

If your company has strict security policies, you may get a prompt asking to allow "Remote Wipe". That's normal. It lets IT remove company data from your phone if you lose it, and it usually doesn't touch your personal photos.

How to fix common iPhone sync problems

Accounts added, and things still don't line up? Start here.

Why is my calendar not syncing?

If updates are slow, say you accept an invitation on your laptop and it takes an hour to reach your phone, check your fetch settings.

1. Go to Settings > Apps > Calendar > Calendar Accounts.
2. Tap Fetch New Data.
3. At the top, make sure Push is on.

With Push, the server sends updates to your phone the moment they happen.

Some accounts don't support Push. For those, pick a Fetch schedule at the bottom:

• Automatically syncs most often and uses the most battery.
• Every 15 Minutes is a reasonable middle ground.
• Manually only updates when you open the app. Avoid it.

Why are events on my iPhone but not other devices?

You create "Lunch with Sarah" on your phone. At your computer, it isn't there.

Usually the event went to a local calendar instead of one in the cloud.

1. Open the event on your iPhone.
2. Look at the Calendar field. Does it say "Home" or "On My iPhone"?
3. If so, the event only exists on your phone.
4. Edit the event and move it to your Google or Exchange calendar.

To stop this happening again, go to your Calendar settings, scroll to Default Calendar and pick your main work or personal account. New events will then save to the cloud.

Why are there duplicate events on my iPhone?

This usually means the same calendar reaches your phone twice. Maybe you added the account in two different ways, or you subscribe to a calendar you already get through your account.

1. Open the Calendar app.
2. Tap Calendars at the bottom.
3. Look for calendars with the same name. If "Work" shows up under two different accounts, untick one. You're seeing the same calendar twice.

How to sync an iPhone calendar with a work PC

The steps above let you see all your calendars on your iPhone. They don't make your calendars share availability with each other.

Add "Dentist Appointment" to your personal Google calendar on your iPhone, and your coworkers on Outlook still see that slot as open. They'll book a meeting over it.

So you end up copying personal events to your work calendar by hand just to block the time. The built-in options stop there.

Using Caltsu for two-way syncing

To have events on one calendar block time on another, you need a sync tool. Caltsu syncs the Google and Microsoft accounts you use on your iPhone. Apple iCloud isn't supported yet, so events that live only in an iCloud calendar don't sync.

Caltsu doesn't just show several calendars side by side. It creates events in them in the background.

Here's how it works:

1. You connect your personal Google calendar, the one on your iPhone, and your work Outlook calendar to Caltsu.
2. You add a personal event on your iPhone.
3. Caltsu creates a matching block on your Outlook calendar.
4. The block doesn't carry the details. Your boss sees "Busy" on your work calendar, not "Therapy Session."

After setup you don't have to do anything, and it works in both directions across Google and Microsoft calendars.

See how Caltsu keeps event details private while syncing.

Keep your iPhone calendar synced

Start with your Calendar accounts in Settings and make sure Push is on so you're not waiting for updates. If you're keeping personal events on your iPhone and a work schedule in Outlook, stop copying events by hand. Let a sync tool block the time so you show up where you're supposed to be.